1. It has to detect sound and activate a 9 volt powered hobby motor that could be found at any radio shack.

2. Once it has been triggered by sound, the motor will remain active for a solid 1 second interval then stop running.

3. If the sound is consistent, the motor will continually run until said sound has ceased.

4. Must be able to use two 9 volts.

5. Needs to be fairly small.

There are boards on the market sold just for this in the world of paintball, however, I am interested in building my own for use in side projects.Also the cost of those boards are around 60 bucks, so that's another reason I want to make this work ( hopefully cheaper).

If anyone can think of the simplest and cheapest way to put something together, I would greatly appreciate the input.